Stephen Ross of Related Cos. is bidding on Sotheby’s 500,000 square-foot building at 1334 York Ave., with a proposal that includes snagging them as a tenant for his Hudson Yards project.

The proposed 1031 tax-free exchange would have Sotheby’s buy — and perhaps partially lease — several hundred thousand square feet in the 750,000 square-foot retail podium that connects the first two office towers at Hudson Yards.